In different harvesting seasons, the lignin, holocellulose and pentosan contents in bamboos didn''t change too much.

至于同为化学主要组成分的木质、维、聚戊醣等成分，则没有节变化。

That means the birch from high longitude and latitude areas will have lower content of the ash, extraction and lignin, higher content of the holocellulose and pentosan in the wood.

这表明，选择较高经区的白桦，可以降低灰分、抽出物、木含量，提高综维和聚戊糖含量。